Grace Design m900 Headphone Amplifier

The Grace Design m900 Headphone Amplifier delivers serious reference-quality headphone monitoring, DA conversion, and preamp functionality in a compact desktop-friendly design that is just as comfortable in a studio rack bag as it is next to your laptop.

Built for audio professionals, critical listeners, and mobile production rigs, the m900 brings Grace Design’s transparent conversion and headphone amp performance into a small, rugged box that punches way above its size. Designed as a portable headphone amplifier, DAC, and stereo preamp, the Grace Design m900 accepts USB, S/PDIF, and TOSLINK digital sources, making it a flexible solution for DAW monitoring, editing, mixing, or high-resolution playback. Its asynchronous USB interface supports PCM audio up to 384kHz and DSD up to 256x, while the AKM 4490 DAC architecture provides clean, detailed conversion with the kind of musical accuracy Grace Design is known for. The m900 also features dual zero-ohm headphone outputs, unbalanced RCA monitor outputs, multiple monitoring modes, channel balance control, and Grace Design’s crossfeed circuit for a more natural headphone listening experience. With both low-power USB bus operation and high-power operation using the included 2A USB power supply, the m900 is ready for everything from efficient headphones to more demanding studio cans.

Incredible DAC Performance
The m900 DAC uses the latest generation AKM 4490 chip, which features 32-bit processing and supports sample rates up to 384kHz PCM or 256x DSD. The USB interface operates in asynchronous mode allowing the m900 to be the clock master which makes the system immune to USB bus jitter. S/PDIF and Toslink inputs allow the m900 to enhance to any DAW interface with true reference quality D/A conversion, headphone monitoring and stereo speaker control.

Intelligent Power Supply Design
An intelligent power supply design allows for two power operation modes – LOW and HIGH. LOW power mode is from USB connector #1, which provides bus power along with data, allowing the m900 to operate from a single connection to your computer. HIGH power power mode is available by connecting the included 2A USB DC power supply to the USB connector #2, which provides additional power for harder to drive headphones.

Superb Audio Performance
Transimpedance amplifier topology coupled to a zero ohm output impedance driver provides headphone performance that is incredibly spacious and transparent with a tight, enveloping low end. Our latest generation crossfeed circuit rounds out the design by simulating an acoustic listening environment in the headphones. Familiar tracks become new again with surprise details, while audio production tasks like tracking, mixing and editing happen faster and easier.

Grace Design m900 Headphone Amplifier Features

• USB, S/PDIF and Toslink digital inputs, supports up to 192kHz (Toslink up to 96kHz)
• Asynchronous USB interface for jitter free computer audio playback, supports up to 384kHz PCM and 256x DSD
• Dual zero ohm output impedance headphone outputs
• Unbalanced level controlled outputs via RCA for connecting to a stereo monitor system
• Compact, portable chassis perfect for travel, desktop or studio
• Mono mode, Left minus Right mode
• 6 Monitoring modes: stereo, L&R swapped, left in both channels, right in both channels, left channel only, right channel only
• Channel balance adjustment
• Low power mode via USB Bus power
• High power mode via included USB 2A power supply
• 4 Different DAC filter settings to tailor playback performance to personal preference
• Simple user setup menu for setup and calibration
• 7 Segment LED display displays level and setup menu information
• Large rotary encoder for volume control and setup menu navigation
• Made in Lyons, CO USA

Grace Design m900 Headphone Amplifier Specifications

• THD+N at Maximum Volume, 1kHz, 22Hz-22kHz BW:
  • @1.0V Out, No Load: <0.002%
  • @1.0V Out, 32 Ohm Load: <0.010%
• Intermodulation Distortion SMTPE/DIN 4:1 50Hz, 7kHz:
  • @1.0V Out, No Load: <0.008%
  • @1.0V Out, 32 Ohm Load: <0.009%
• Frequency Response +/-3dB:
  • Fs=96kHz: 0.5-45.9kHz
• Dynamic Range:
  • 20-22kHz Bandwidth: 112 dB
  • 20-22kHz Bandwidth & A weighting Filter: 115 dB
• Output Noise:
  • 20-22kHz, Volume=0-90: -106dBV
  • A Weighting Filter, Volume = 0-90: -109dBV
  • 20-22kHz, Volume=90.5-99.5: -96dBV
  • A Weighting Filter, Volume = 90.5-99.5: -98dBV
• Crosstalk:
  • 100Hz: <107dB
  • 1kHz: <98dB
  • 20kHz: <72dB
• Attenuation Range: 0 to -99dB, 0.5dB steps
• Crosstalk Tracking Accuracy: +/-0.05dB
• Maximum Output Level, No Load:
  • Low Power Mode: +14.1dBV (5.1V)
  • High Power Mode: +15.5dBV (6.0V)
• Impedances:
  • Headphone Output: 0.08 Ohms
  • Line Output: 47.5 Ohms
• Power Consumption:
  • Max, High Power Mode: 8.0W
  • Max, Low Power Mode: 2.5W
• Dimensions: 4" x 5.25" x 1.8"

Grace Design m900 Headphone Amplifier Includes

• Grace Design m900 Headphone Amplifier
• Owners Manual
• Manufacturer Warranty